I have an IFTTT recipe that adds a value to a Beeminder goal whenever a Google Calendar event with a certain title occurs.
When I first set up this recipe last year, it would fire 15 minutes before the event. IFTTT has recently added an option to specify how early a recipe should fire, and I think they’ve changed the default firing time to 0 minutes before the event.
So, if your IFTTT-Google Calendar recipe has been firing later than expected, this change might be why.